1. Field of the Invention
The present invention relates to image processing apparatuses and information processing methods. In particular, the present invention relates to image processing in which a conversion table is created for converting a color independent of a device to a color in a device color space on the basis of a colorimetry result of a color patch output by an output device.
2. Description of the Related Art
Color conversion techniques which use profiles describing color characteristics of input/output devices in tables have been used for improving color reproduction processing of printers. In such techniques, conversion tables for converting color data from input device color spaces into device-independent color spaces and also converting color data from device-independent color spaces into output device color spaces (i.e., look-up tables (LUTs)) are used for realizing color reproduction between input and output through LUT operations. Thus, the color reproduction performance of printers largely depends on the accuracy of such conversion tables. In particular, precision in creating LUTs for conversion from device-independent color spaces into printer-device color spaces is important for accurate color reproduction.
To create conversion tables, data representing a correspondence relationship between CMYK signals in printers and device-independent signals (i.e., calorimetric tables) is necessary. In general, such data can be obtained by measuring a plurality of color patches output from a printer.
However, since CMYK color spaces used in color printers may depend on the characteristics of the printers, it is difficult to flexibly apply processes for creating conversion tables using only calorimetric tables to various devices. In particular, such processes are difficult to apply to conversion tables for conversion from device-independent color spaces to printer color spaces, since they are strongly affected by nonlinear output characteristics of color printers. To address this, techniques have been developed for increasing color reproduction accuracy by using parameters in addition to calorimetric data, such as density characteristics representing output characteristics of color printers.
For example, Japanese Patent Laid-Open No. 2003-125223 discloses a technique for overcoming nonlinear characteristics of a printer by performing gradation correction processing using linear density of the printer.